This is a proposal for an ADAMHA Research Scientist Award, submitted as a competitive renewal, following ten years support of Dr. Daniel F. Kripke at RSDA Level II. First, clinical studies of patients with affective disorders will examine treatment effects of bright light, the role of melatonin, and the role of circadian phase disorders. The major clinical study is a controlled trial of bright light treatment of patients with major depressive disorders. Effects of seven days of treatment with 1500-2500 lux bright white light from 8:00 to 11:00 P.M. will be contrasted with effects on subjects randomized to a control treatment with dim red light. Initial results suggest that one week treatment with bright white light is somewhat more effective than one week treatment with amitryptyline. Second, VA-funded research examines related chronobiologic issues in rodent models. We will explore effects of lithium and clorgyline on circadian rhythms in wheel running activity, body temperature rhythm, and suprachiasmatic nucleus multiple unit firing. The influence of lithium and clorgyline on phase-response curves will also be examined. Third, studies of sleep apnea will be pursued primarily from an epidemiologic orientation. An ongoing study examines the mortality risk associated with sleep apnea in a medical in-patient sample of subjects over age 65.0. A second project in UCSD's Teaching Nursing Home explores the association of apnea in a nursing home sample with hypnotic drug use and with dementia.